wheels, 108 swap to 103 problem

canticle

Member
I am swapping , on a 2004 Z4 3.0i Roadster, the OE 108 18" split rim wheels for 103 17 wheels (with slightly taller tyres to compensate, 45s rather than 40s). This is for a slightly smoother ride and to give me a chance to refurbish the 108s whilst making comparison.
But, despite both being OEM with identical 47mm offsets, I have clearance issues with the shocks; the wheels spin freely whilst the car is jacked up but rub once the suspension is even normally loaded. It seems only to be a problem with both front wheels.
What have I got wrong? Do I need spacers (I guess) and what thickness, make, supplier, cost etc.?

Help, please !!

Phil
 
This maybe a silly question, but you know they are a staggered set up?

You don't have the backs on the front do you?
 
ha, entirely possible 8) ! I had assumed that all four 103s, all being 225 tyred, were identical? oh, how I wish you are right!
 
103s were fitted on my car when I bought it and I'm fairly certain that they are a square set up and all 17x8" et47. :( Check the profile/shape of the sidewall on the 103 tyres. If they are fatter/more curved then this may be the problem. Crappy Bridgestone runflats with a fairly flat sidewall were on mine and they didn't rub anywhere :thumbsup:
 
How unusual! 103 wheels themselves are a square set up, but no reason why the rubber couldn't have been put on in a 'staggered' fitment.

Best bet is to take some pictures OP. Confirming tyre sizes? Have you noticed where it's rubbing?

You've got a pre-facelift, so car should work with 16" wheels!
 
I went 108 to 103 and much prefer it, the 108's are a pain to refurb and a bit blingy for me, 17's look better proportioned to the car but I accept that my opinion is probably in the minority, even though I am right :poke: :rofl:

103's are square set so all tyres should be same, I had no problem on my 2004, 3.0.
 
well, I have checked every aspect again. All the 103s are identical and it's their rims are rubbing, just the front shocks; it isn't the tyres but metal on metal.
I wonder if the shocks have been changed for something fatter ? How would I check ? It has become tedious swapping all four wheels back and forth twice now, in broiling temperature and humidity; I'm knackered!
I checked every dimension on the front 108s and, apart from the rim diameter, they are identical.
 
I initially had the same idea, took the (completely shot) 107's off and put some 104's (16's) on before moving to 89's which are 17's. Which for now is fine. Plus they're slightly cheaper to rubber up! The 17" alloys are a tad shot so I'll be going to 18's after. And can always go back!

I've had 16's and 17's on mine with no issues. Not sure why you're getting a problem? :? For some reason your wheels are sitting further inside than they should be? Or like you said some component is stick out from the suspension?

The only thing I can think of is cracked springs? Although more common with rears, but possibly fronts are cracked and thus changed geometry causing rubbing, or been replaced (for whatever reason) with something that isn't 100% correct.

Have you tried driving it for some distance? Like slowly around the neighbourhood? Possibly it could 'settle' and configure itself to not rub?

Failing that do you know when you last had a wheel alignment?
 
I think it unlikely anything would "reconfigure", it's hardly an electronic problem. :(
There are no broken springs, I checked. :(
 
When I change wheels on my Zed, the rear springs noticeably take a short drive to settle.
i.e. the gap between the tyre and arch is quite large (due to spring being uncompressed during wheel change) then settles down to a normal ride height after a short drive - what I call the reconfigure (I suspect here is a more correct / technical term!). I'm sure something similar could happen with the front...

If it's still playing up and you want the 103's on then easiest, most hassle free thing I can suggest is to get some wheel spacers. Obviously the best thing to do, is find out what the real problem is, rather than adding the spacer and not dealing with it? If you see what I mean?

All the best! :thumbsup:
 
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